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Jung KW, Lee SH, Lee KT, Bahn YS. Sensing and responding to host-derived stress signals: lessons from fungal meningitis pathogen. Curr Opin Microbiol 2024; 80:102514. [PMID: 39024914 DOI: 10.1016/j.mib.2024.102514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 06/25/2024] [Accepted: 07/01/2024] [Indexed: 07/20/2024]
Abstract
The sophisticated ability of living organisms to sense and respond to external stimuli is critical for survival. This is particularly true for fungal pathogens, where the capacity to adapt and proliferate within a host is essential. To this end, signaling pathways, whether evolutionarily conserved or unique, have been refined through interactions with the host. Cryptococcus neoformans, an opportunistic fungal pathogen, is responsible for over 190,000 cases and an estimated 147,000 annual deaths globally. Extensive research over the past decades has shed light on the signaling pathways underpinning the pathogenicity of C. neoformans, as well as the host's responses during infection. In this context, we delineate the regulatory mechanisms employed by C. neoformans to detect and react to stresses derived from the host.
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Affiliation(s)
- Kwang-Woo Jung
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeonbuk, Republic of Korea
| | - Seung-Heon Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Jeonbuk, Republic of Korea.
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
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2
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King WR, Acosta-Zaldívar M, Qi W, Cherico N, Cooke L, Köhler JR, Patton-Vogt J. Glycerophosphocholine provision rescues Candida albicans growth and signaling phenotypes associated with phosphate limitation. mSphere 2023; 8:e0023123. [PMID: 37843297 PMCID: PMC10732039 DOI: 10.1128/msphere.00231-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/30/2023] [Indexed: 10/17/2023] Open
Abstract
IMPORTANCE Candida albicans is the most commonly isolated species from patients suffering from invasive fungal disease. C. albicans is most commonly a commensal organism colonizing a variety of niches in the human host. The fungus must compete for resources with the host flora to acquire essential nutrients such as phosphate. Phosphate acquisition and homeostasis have been shown to play a key role in C. albicans virulence, with several genes involved in these processes being required for normal virulence and several being upregulated during infection. In addition to inorganic phosphate (Pi), C. albicans can utilize the lipid-derived metabolite glycerophosphocholine (GPC) as a phosphate source. As GPC is available within the human host, we examined the role of GPC in phosphate homeostasis in C. albicans. We find that GPC can substitute for Pi by many though not all criteria and is likely a relevant physiological phosphate source for C. albicans.
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Affiliation(s)
- William R. King
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Maikel Acosta-Zaldívar
- Department of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Wanjun Qi
- Department of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Nicholas Cherico
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Lauren Cooke
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Julia R. Köhler
- Department of Infectious Diseases, Boston Children’s Hospital/Harvard Medical School, Boston, Massachusetts, USA
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
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3
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Chabert V, Kim GD, Qiu D, Liu G, Michaillat Mayer L, Jamsheer K M, Jessen HJ, Mayer A. Inositol pyrophosphate dynamics reveals control of the yeast phosphate starvation program through 1,5-IP 8 and the SPX domain of Pho81. eLife 2023; 12:RP87956. [PMID: 37728314 PMCID: PMC10511240 DOI: 10.7554/elife.87956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023] Open
Abstract
Eukaryotic cells control inorganic phosphate to balance its role as essential macronutrient with its negative bioenergetic impact on reactions liberating phosphate. Phosphate homeostasis depends on the conserved INPHORS signaling pathway that utilizes inositol pyrophosphates and SPX receptor domains. Since cells synthesize various inositol pyrophosphates and SPX domains bind them promiscuously, it is unclear whether a specific inositol pyrophosphate regulates SPX domains in vivo, or whether multiple inositol pyrophosphates act as a pool. In contrast to previous models, which postulated that phosphate starvation is signaled by increased production of the inositol pyrophosphate 1-IP7, we now show that the levels of all detectable inositol pyrophosphates of yeast, 1-IP7, 5-IP7, and 1,5-IP8, strongly decline upon phosphate starvation. Among these, specifically the decline of 1,5-IP8 triggers the transcriptional phosphate starvation response, the PHO pathway. 1,5-IP8 inactivates the cyclin-dependent kinase inhibitor Pho81 through its SPX domain. This stimulates the cyclin-dependent kinase Pho85-Pho80 to phosphorylate the transcription factor Pho4 and repress the PHO pathway. Combining our results with observations from other systems, we propose a unified model where 1,5-IP8 signals cytosolic phosphate abundance to SPX proteins in fungi, plants, and mammals. Its absence triggers starvation responses.
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Affiliation(s)
- Valentin Chabert
- Département d'immunobiologie, Université de LausanneEpalingesSwitzerland
| | - Geun-Don Kim
- Département d'immunobiologie, Université de LausanneEpalingesSwitzerland
| | - Danye Qiu
- Institute of Organic Chemistry, Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
| | - Guizhen Liu
- Institute of Organic Chemistry, Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
| | | | | | - Henning J Jessen
- Institute of Organic Chemistry, Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
| | - Andreas Mayer
- Département d'immunobiologie, Université de LausanneEpalingesSwitzerland
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Lessons from protozoans: Phosphate sensing and polyphosphate storage in fungi. PLoS Pathog 2022; 18:e1010298. [PMID: 35239748 PMCID: PMC8893339 DOI: 10.1371/journal.ppat.1010298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Bhalla K, Qu X, Kretschmer M, Kronstad JW. The phosphate language of fungi. Trends Microbiol 2021; 30:338-349. [PMID: 34479774 DOI: 10.1016/j.tim.2021.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 11/20/2022]
Abstract
Phosphate is an essential macronutrient for fungal proliferation as well as a key mediator of antagonistic, beneficial, and pathogenic interactions between fungi and other organisms. In this review, we summarize recent insights into the integration of phosphate metabolism with mechanisms of fungal adaptation that support growth and survival. In particular, we highlight aspects of phosphate sensing important for responses to stress and regulation of cell-surface changes with an impact on fungal pathogenesis, host immune responses, and disease outcomes. Additionally, new studies provide insights into the influence of phosphate availability on cooperative or antagonistic interactions between fungi and other microbes, the associations of mycorrhizal and endophytic fungi with plants, and connections with plant immunity. Overall, phosphate homeostasis is emerging as an integral part of fungal metabolism and communication to support diverse lifestyles.
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Affiliation(s)
- Kabir Bhalla
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Xianya Qu
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Matthias Kretschmer
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - James W Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada.
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6
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Lev S, Bowring B, Desmarini D, Djordjevic JT. Inositol polyphosphate-protein interactions: Implications for microbial pathogenicity. Cell Microbiol 2021; 23:e13325. [PMID: 33721399 PMCID: PMC9286782 DOI: 10.1111/cmi.13325] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/03/2021] [Accepted: 03/07/2021] [Indexed: 11/29/2022]
Abstract
Inositol polyphosphates (IPs) and inositol pyrophosphates (PP-IPs) regulate diverse cellular processes in eukaryotic cells. IPs and PP-IPs are highly negatively charged and exert their biological effects by interacting with specific protein targets. Studies performed predominantly in mammalian cells and model yeasts have shown that IPs and PP-IPs modulate target function through allosteric regulation, by promoting intra- and intermolecular stabilization and, in the case of PP-IPs, by donating a phosphate from their pyrophosphate (PP) group to the target protein. Technological advances in genetics have extended studies of IP function to microbial pathogens and demonstrated that disrupting PP-IP biosynthesis and PP-IP-protein interaction has a profound impact on pathogenicity. This review summarises the complexity of IP-mediated regulation in eukaryotes, including microbial pathogens. It also highlights examples of poor conservation of IP-protein interaction outcome despite the presence of conserved IP-binding domains in eukaryotic proteomes.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Bethany Bowring
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
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Abstract
In the human-pathogenic fungus Cryptococcus neoformans, the inositol polyphosphate signaling pathway is critical for virulence. We recently demonstrated the key role of the inositol pyrophosphate IP7 (isomer 5-PP-IP5) in driving fungal virulence; however, the mechanism of action remains elusive. Using genetic and biochemical approaches, and mouse infection models, we show that IP7 synthesized by Kcs1 regulates fungal virulence by binding to a conserved lysine surface cluster in the SPX domain of Pho81. Pho81 is the cyclin-dependent kinase (CDK) inhibitor of the phosphate signaling (PHO) pathway. We also provide novel mechanistic insight into the role of IP7 in PHO pathway regulation by demonstrating that IP7 functions as an intermolecular "glue" to stabilize Pho81 association with Pho85/Pho80 and, hence, promote PHO pathway activation and phosphate acquisition. Blocking IP7-Pho81 interaction using site-directed mutagenesis led to a dramatic loss of fungal virulence in a mouse infection model, and the effect was similar to that observed following PHO81 gene deletion, highlighting the key importance of Pho81 in fungal virulence. Furthermore, our findings provide additional evidence of evolutionary divergence in PHO pathway regulation in fungi by demonstrating that IP7 isomers have evolved different roles in PHO pathway control in C. neoformans and nonpathogenic yeast.IMPORTANCE Invasive fungal diseases pose a serious threat to human health globally with >1.5 million deaths occurring annually, 180,000 of which are attributable to the AIDS-related pathogen, Cryptococcus neoformans Here, we demonstrate that interaction of the inositol pyrophosphate, IP7, with the CDK inhibitor protein, Pho81, is instrumental in promoting fungal virulence. IP7-Pho81 interaction stabilizes Pho81 association with other CDK complex components to promote PHO pathway activation and phosphate acquisition. Our data demonstrating that blocking IP7-Pho81 interaction or preventing Pho81 production leads to a dramatic loss in fungal virulence, coupled with Pho81 having no homologue in humans, highlights Pho81 function as a potential target for the development of urgently needed antifungal drugs.
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8
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Lev S, Li C, Desmarini D, Sorrell TC, Saiardi A, Djordjevic JT. Fungal Kinases With a Sweet Tooth: Pleiotropic Roles of Their Phosphorylated Inositol Sugar Products in the Pathogenicity of Cryptococcus neoformans Present Novel Drug Targeting Opportunities. Front Cell Infect Microbiol 2019; 9:248. [PMID: 31380293 PMCID: PMC6660261 DOI: 10.3389/fcimb.2019.00248] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022] Open
Abstract
Invasive fungal pathogens cause more than 300 million serious human infections and 1.6 million deaths per year. A clearer understanding of the mechanisms by which these fungi cause disease is needed to identify novel targets for urgently needed therapies. Kinases are key components of the signaling and metabolic circuitry of eukaryotic cells, which include fungi, and kinase inhibition is currently being exploited for the treatment of human diseases. Inhibiting evolutionarily divergent kinases in fungal pathogens is a promising avenue for antifungal drug development. One such group of kinases is the phospholipase C1-dependent inositol polyphosphate kinases (IPKs), which act sequentially to transfer a phosphoryl group to a pre-phosphorylated inositol sugar (IP). This review focuses on the roles of fungal IPKs and their IP products in fungal pathogenicity, as determined predominantly from studies performed in the model fungal pathogen Cryptococcus neoformans, and compares them to what is known in non-pathogenic model fungi and mammalian cells to highlight potential drug targeting opportunities.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Cecilia Li
- Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology-Public Health, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Tania C Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
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9
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Lev S, Rupasinghe T, Desmarini D, Kaufman-Francis K, Sorrell TC, Roessner U, Djordjevic JT. The PHO signaling pathway directs lipid remodeling in Cryptococcus neoformans via DGTS synthase to recycle phosphate during phosphate deficiency. PLoS One 2019; 14:e0212651. [PMID: 30789965 PMCID: PMC6383925 DOI: 10.1371/journal.pone.0212651] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 02/06/2019] [Indexed: 12/16/2022] Open
Abstract
The phosphate sensing and acquisition (PHO) pathway of Cryptococcus neoformans is essential for growth in phosphate-limiting conditions and for dissemination of infection in a mouse model. Its key transcription factor, Pho4, regulates expression of genes controlling the acquisition of phosphate from both external and cellular sources. One such gene, BTA1, is highly up-regulated during phosphate starvation. Given that a significant proportion of cellular phosphate is incorporated into phospholipids, and that the Pho4-dependent BTA1 gene encodes an enzyme predicted to catalyse production of a phosphorus-free betaine lipid, we investigated whether phospholipids provide an accessible reservoir of phosphate during phosphate deficiency. By comparing lipid profiles of phosphate-starved WT C. neoformans, PHO4 (pho4Δ) and BTA1 (bta1Δ) deletion mutants using thin layer chromatography and liquid chromatography mass spectrometry, we showed that phosphatidylcholine (PC) is substituted by the phosphorus-free betaine lipids diacylglyceryl-N,N,N-trimethylhomoserine (DGTS) and diacylgyceryl hydroxymethyl-N,N,N-trimethyl-beta-alanine (DGTA) in a Pho4- and Bta1-dependent manner, and that BTA1 encodes a functional DGTS synthase. Synthesis of DGTA tightly correlated with that of DGTS, consistent with DGTS being the precursor of DGTA. Similar to pho4Δ, bta1Δ grew more slowly than WT in cell culture medium (RPMI) and was hypovirulent in a murine model of cryptococcosis. In contrast to pho4Δ, bta1Δ tolerated alkaline pH and disseminated to the brain. Our results demonstrate that Bta1-dependent substitution of PC by betaine lipids is tightly regulated in C. neoformans by the PHO pathway, to conserve phosphate and preserve membrane integrity and function. This phospholipid remodeling strategy may also contribute to cryptococcal virulence during host infection.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, Fungal Pathogenesis Group, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Thusitha Rupasinghe
- Metabolomics Australia, School of Biosciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, Fungal Pathogenesis Group, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
| | - Keren Kaufman-Francis
- Centre for Infectious Diseases and Microbiology, Fungal Pathogenesis Group, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Tania Christine Sorrell
- Centre for Infectious Diseases and Microbiology, Fungal Pathogenesis Group, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Ute Roessner
- Metabolomics Australia, School of Biosciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, Fungal Pathogenesis Group, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
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Lev S, Djordjevic JT. Why is a functional PHO pathway required by fungal pathogens to disseminate within a phosphate-rich host: A paradox explained by alkaline pH-simulated nutrient deprivation and expanded PHO pathway function. PLoS Pathog 2018; 14:e1007021. [PMID: 29928051 PMCID: PMC6013017 DOI: 10.1371/journal.ppat.1007021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, Australia
- Sydney Medical School-Westmead, University of Sydney, Westmead, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, Australia
- Sydney Medical School-Westmead, University of Sydney, Westmead, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
- * E-mail:
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Martins MP, Gomes EV, Sanches PR, Pedersoli WR, Martinez-Rossi NM, Rossi A. mus-52 disruption and metabolic regulation in Neurospora crassa: Transcriptional responses to extracellular phosphate availability. PLoS One 2018; 13:e0195871. [PMID: 29668735 PMCID: PMC5905970 DOI: 10.1371/journal.pone.0195871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 03/30/2018] [Indexed: 12/01/2022] Open
Abstract
Advances in the understanding of molecular systems depend on specific tools like the disruption of genes to produce strains with the desired characteristics. The disruption of any mutagen sensitive (mus) genes in the model fungus Neurospora crassa, i.e. mus-51, mus-52, or mus-53, orthologous to the human genes KU70, KU80, and LIG4, respectively, provides efficient tools for gene targeting. Accordingly, we used RNA-sequencing and reverse transcription-quantitative polymerase chain reaction amplification techniques to evaluate the effects of mus-52 deletion in N. crassa gene transcriptional modulation, and thus, infer its influence regarding metabolic response to extracellular availability of inorganic phosphate (Pi). Notably, the absence of MUS-52 affected the transcription of a vast number of genes, highlighting the expression of those coding for transcription factors, kinases, circadian clocks, oxi-reduction balance, and membrane- and nucleolus-related proteins. These findings may provide insights toward the KU molecular mechanisms, which have been related to telomere maintenance, apoptosis, DNA replication, and gene transcription regulation, as well as associated human conditions including immune system disorders, cancer, and aging.
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Affiliation(s)
- Maíra P. Martins
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Eriston V. Gomes
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Pablo R. Sanches
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Wellington R. Pedersoli
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Nilce M. Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
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Evolutionary conservation of a core fungal phosphate homeostasis pathway coupled to development in Blastocladiella emersonii. Fungal Genet Biol 2018; 115:20-32. [PMID: 29627365 DOI: 10.1016/j.fgb.2018.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 01/08/2023]
Abstract
The model yeast Saccharomyces cerevisiae elicits a transcriptional response to phosphate (Pi) depletion. To determine the origins of the phosphate response (PHO) system, we bioinformatically identified putative PHO components in the predicted proteomes of diverse fungi. Our results suggest that the PHO system is ancient; however, components have been expanded or lost in different fungal lineages. To show that a similar physiological response is present in deeply-diverging fungi we examined the transcriptional and physiological response of PHO genes to Pi depletion in the blastocladiomycete Blastocladiella emersonii. Our physiological experiments indicate that B. emersonii relies solely on high-affinity Na+-independent Pho84-like transporters. In response to Pi depletion, BePho84 paralogues were 4-8-fold transcriptionally upregulated, whereas several other PHO homologues like phosphatases and vacuolar transporter chaperone (VTC) complex components show 2-3-fold transcriptional upregulation. Since Pi has been shown to be important during the development of B. emersonii, we sought to determine if PHO genes are differentially regulated at different lifecycle stages. We demonstrate that a similar set of PHO transporters and phosphatases are upregulated at key points during B. emersonii development. Surprisingly, some genes upregulated during Pi depletion, including VTC components, are repressed at these key stages of development indicating that PHO genes are regulated by different pathways in different developmental and environmental situations. Overall, our findings indicate that a complex PHO network existed in the ancient branches of the fungi, persists in diverse extant fungi, and that this ancient network is likely to be involved in development and cell cycle regulation.
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13
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Mechanisms of Pulmonary Escape and Dissemination by Cryptococcus neoformans. J Fungi (Basel) 2018; 4:jof4010025. [PMID: 29463005 PMCID: PMC5872328 DOI: 10.3390/jof4010025] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/09/2018] [Accepted: 02/16/2018] [Indexed: 12/15/2022] Open
Abstract
Cryptococcus neoformans is a common environmental saprophyte and human fungal pathogen that primarily causes disease in immunocompromised individuals. Similar to many environmentally acquired human fungal pathogens, C. neoformans initiates infection in the lungs. However, the main driver of mortality is invasive cryptococcosis leading to fungal meningitis. After C. neoformans gains a foothold in the lungs, a critical early step in invasion is transversal of the respiratory epithelium. In this review, we summarize current knowledge relating to pulmonary escape. We focus on fungal factors that allow C. neoformans to disseminate from the lungs via intracellular and extracellular routes.
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Wang Y, Zhang S, Zhu Z, Shen H, Lin X, Jin X, Jiao X, Zhao ZK. Systems analysis of phosphate-limitation-induced lipid accumulation by the oleaginous yeast Rhodosporidium toruloides. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:148. [PMID: 29849765 PMCID: PMC5968551 DOI: 10.1186/s13068-018-1134-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 04/28/2018] [Indexed: 05/12/2023]
Abstract
BACKGROUND Lipid accumulation by oleaginous microorganisms is of great scientific interest and biotechnological potential. While nitrogen limitation has been routinely employed, low-cost raw materials usually contain rich nitrogenous components, thus preventing from efficient lipid production. Inorganic phosphate (Pi) limitation has been found sufficient to promote conversion of sugars into lipids, yet the molecular basis of cellular response to Pi limitation and concurrent lipid accumulation remains elusive. RESULTS Here, we performed multi-omic analyses of the oleaginous yeast Rhodosporidium toruloides to shield lights on Pi-limitation-induced lipid accumulation. Samples were prepared under Pi-limited as well as Pi-repleted chemostat conditions, and subjected to analysis at the transcriptomic, proteomic, and metabolomic levels. In total, 7970 genes, 4212 proteins, and 123 metabolites were identified. Results showed that Pi limitation facilitates up-regulation of Pi-associated metabolism, RNA degradation, and triacylglycerol biosynthesis while down-regulation of ribosome biosynthesis and tricarboxylic acid cycle. Pi limitation leads to dephosphorylation of adenosine monophosphate and the allosteric activator of isocitrate dehydrogenase key to lipid biosynthesis. It was found that NADPH, the key cofactor for fatty acid biosynthesis, is limited due to reduced flux through the pentose phosphate pathway and transhydrogenation cycle and that this can be overcome by over-expression of an endogenous malic enzyme. These phenomena are found distinctive from those under nitrogen limitation. CONCLUSIONS Our data suggest that Pi limitation activates Pi-related metabolism, RNA degradation, and TAG biosynthesis while inhibits ribosome biosynthesis and TCA cycle, leading to enhanced carbon fluxes into lipids. The information greatly enriches our understanding on microbial oleaginicity and Pi-related metabolism. Importantly, systems data may facilitate designing advanced cell factories for production of lipids and related oleochemicals.
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Affiliation(s)
- Yanan Wang
- Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
| | - Sufang Zhang
- Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
| | - Zhiwei Zhu
- Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
| | - Hongwei Shen
- Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
| | - Xinping Lin
- School of Food Science and Technology, Dalian Polytechnic University, Dalian, 116034 People’s Republic of China
| | - Xiang Jin
- Beijing Bio-Fly Bioscience Co. Ltd., Beijing, 100080 People’s Republic of China
| | - Xiang Jiao
- Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
| | - Zongbao Kent Zhao
- Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
- Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 People’s Republic of China
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15
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Novel biosynthetic pathway for sulfur amino acids in Cryptococcus neoformans. Curr Genet 2017; 64:681-696. [PMID: 29159425 DOI: 10.1007/s00294-017-0783-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/01/2017] [Accepted: 11/16/2017] [Indexed: 12/27/2022]
Abstract
We elucidated a unique feature of sulfur metabolism in Cryptococcus neoformans. C. neoformans produces cysteine solely by the O-acetylserine pathway that consists of serine-O-acetyl transferase and cysteine synthase. We designated the gene encoding the former enzyme CYS2 (locus tag CNE02740) and the latter enzyme CYS1 (locus tag CNL05880). The cys1Δmutant strain was found to be avirulent in a murine infection model. Methionine practically does not support growth of the cys1Δ strain, and cysteine does not serve as a methionine source, indicating that the transsulfuration pathway does not contribute to sulfur amino acid synthesis in C. neoformans. Among the genes encoding enzymes catalyzing the reactions from homoserine to methionine, the gene corresponding to the Saccharomyces cerevisiae MET17 encoding O-acetylhomoserine sulfhydrylase (Met17p) had remained to be identified in C. neoformans. By genetic analysis of Met- mutants obtained by Agrobacterium tumefaciens-mediated mutagenesis, we concluded that Cnc01220, most similar to Str2p (36% identity), cystathionine-γ-synthase, in the Saccharomyces genome, is the C. neoformans version of O-acetylhomoserine sulfhydrylase. We designated CNC01220 as MET17. The C. neoformans met3Δ mutant defective in the first step of the sulfate assimilation pathway, sulfate adenylyltransferase, barely uses methionine as a sulfur source, whereas it uses cysteine efficiently. The poor utilization of methionine by the met3Δ mutant is most probably due to the absence of the transsulfuration pathway, causing an incapability of C. neoformans to produce cysteine and hydrogen sulfide from methionine. When cysteine is used as a sulfur source, methionine is likely produced de novo by using hydrogen sulfide derived from cysteine via an unidentified pathway. Altogether, the unique features of sulfur amino acid metabolism in C. neoformans will make this fungus a valuable experimental system to develop anti-fungal agents and to investigate physiology of hydrogen sulfide.
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16
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Phosphate Acquisition and Virulence in Human Fungal Pathogens. Microorganisms 2017; 5:microorganisms5030048. [PMID: 28829379 PMCID: PMC5620639 DOI: 10.3390/microorganisms5030048] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 01/23/2023] Open
Abstract
The ability of pathogenic fungi to acquire essential macro and micronutrients during infection is a well-established virulence trait. Recent studies in the major human fungal pathogens Candida albicans and Cryptococcus neoformans have revealed that acquisition of the essential macronutrient, phosphate, is essential for virulence. The phosphate sensing and acquisition pathway in fungi, known as the PHO pathway, has been extensively characterized in the model yeast Saccharomyces cerevisiae. In this review, we highlight recent advances in phosphate sensing and signaling mechanisms, and use the S. cerevisiae PHO pathway as a platform from which to compare the phosphate acquisition and storage strategies employed by several human pathogenic fungi. We also explore the multi-layered roles of phosphate acquisition in promoting fungal stress resistance to pH, cationic, and oxidative stresses, and describe emerging roles for the phosphate storage molecule polyphosphate (polyP). Finally, we summarize the recent studies supporting the necessity of phosphate acquisition in mediating the virulence of human fungal pathogens, highlighting the concept that this requirement is intimately linked to promoting resistance to host-imposed stresses.
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17
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Arras SDM, Chitty JL, Wizrah MSI, Erpf PE, Schulz BL, Tanurdzic M, Fraser JA. Sirtuins in the phylum Basidiomycota: A role in virulence in Cryptococcus neoformans. Sci Rep 2017; 7:46567. [PMID: 28429797 PMCID: PMC5399365 DOI: 10.1038/srep46567] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/17/2017] [Indexed: 02/07/2023] Open
Abstract
Virulence of Cryptococcus neoformans is regulated by a range of transcription factors, and is also influenced by the acquisition of adaptive mutations during infection. Beyond the temporal regulation of virulence factor production by transcription factors and these permanent microevolutionary changes, heritable epigenetic modifications such as histone deacetylation may also play a role during infection. Here we describe the first comprehensive analysis of the sirtuin class of NAD+ dependent histone deacetylases in the phylum Basidiomycota, identifying five sirtuins encoded in the C. neoformans genome. Each sirtuin gene was deleted and a wide range of phenotypic tests performed to gain insight into the potential roles they play. Given the pleiotropic nature of sirtuins in other species, it was surprising that only two of the five deletion strains revealed mutant phenotypes in vitro. However, cryptic consequences of the loss of each sirtuin were identified through whole cell proteomics, and mouse infections revealed a role in virulence for SIR2, HST3 and HST4. The most intriguing phenotype was the repeated inability to complement mutant phenotypes through the reintroduction of the wild-type gene. These data support the model that regulation of sirtuin activity may be employed to enable a drastic alteration of the epigenetic landscape and virulence of C. neoformans.
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Affiliation(s)
- Samantha D M Arras
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Jessica L Chitty
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Maha S I Wizrah
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Paige E Erpf
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Benjamin L Schulz
- School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Milos Tanurdzic
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - James A Fraser
- Australian Infectious Diseases Research Centre, Queensland, Australia.,School of Chemistry &Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
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18
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Pho4 Is Essential for Dissemination of Cryptococcus neoformans to the Host Brain by Promoting Phosphate Uptake and Growth at Alkaline pH. mSphere 2017; 2:mSphere00381-16. [PMID: 28144629 PMCID: PMC5266496 DOI: 10.1128/msphere.00381-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 12/30/2016] [Indexed: 12/30/2022] Open
Abstract
Phosphate acquisition by fungi is regulated by the phosphate-sensing and acquisition (PHO) signaling pathway. Cryptococcus neoformans disseminates from the lung to the brain and is the commonest cause of fungal meningitis worldwide. To investigate the contribution of PHO signaling to cryptococcal dissemination, we characterized a transcription factor knockout strain (hlh3Δ/pho4Δ) defective in phosphate acquisition. Despite little similarity with other fungal Pho4 proteins, Hlh3/Pho4 functioned like a typical phosphate-responsive transcription factor in phosphate-deprived cryptococci, accumulating in nuclei and triggering expression of genes involved in phosphate acquisition. The pho4Δ mutant strain was susceptible to a number of stresses, the effect of which, except for alkaline pH, was alleviated by phosphate supplementation. Even in the presence of phosphate, the PHO pathway was activated in wild-type cryptococci at or above physiological pH, and under these conditions, the pho4Δ mutant had a growth defect and compromised phosphate uptake. The pho4Δ mutant was hypovirulent in a mouse inhalation model, where dissemination to the brain was reduced dramatically, and markedly hypovirulent in an intravenous dissemination model. The pho4Δ mutant was not detected in blood, nor did it proliferate significantly when cultured with peripheral blood monocytes. In conclusion, dissemination of infection and the pathogenesis of meningitis are dependent on cryptococcal phosphate uptake and stress tolerance at alkaline pH, both of which are Pho4 dependent. IMPORTANCE Cryptococcal meningitis is fatal without treatment and responsible for more than 500,000 deaths annually. To be a successful pathogen, C. neoformans must obtain an adequate supply of essential nutrients, including phosphate, from various host niches. Phosphate acquisition in fungi is regulated by the PHO signaling cascade, which is activated when intracellular phosphate decreases below a critical level. Induction of phosphate acquisition genes leads to the uptake of free phosphate via transporters. By blocking the PHO pathway using a Pho4 transcription factor mutant (pho4Δ mutant), we demonstrate the importance of the pathway for cryptococcal dissemination and the establishment of brain infection in murine models. Specifically, we show that reduced dissemination of the pho4Δ mutant to the brain is due to an alkaline pH tolerance defect, as alkaline pH mimics the conditions of phosphate deprivation. The end result is inhibited proliferation in host tissues, particularly in blood.
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19
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Culibrk L, Croft CA, Tebbutt SJ. Systems Biology Approaches for Host-Fungal Interactions: An Expanding Multi-Omics Frontier. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2016; 20:127-38. [PMID: 26885725 PMCID: PMC4799697 DOI: 10.1089/omi.2015.0185] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Opportunistic fungal infections are an increasing threat for global health, and for immunocompromised patients in particular. These infections are characterized by interaction between fungal pathogen and host cells. The exact mechanisms and the attendant variability in host and fungal pathogen interaction remain to be fully elucidated. The field of systems biology aims to characterize a biological system, and utilize this knowledge to predict the system's response to stimuli such as fungal exposures. A multi-omics approach, for example, combining data from genomics, proteomics, metabolomics, would allow a more comprehensive and pan-optic "two systems" biology of both the host and the fungal pathogen. In this review and literature analysis, we present highly specialized and nascent methods for analysis of multiple -omes of biological systems, in addition to emerging single-molecule visualization techniques that may assist in determining biological relevance of multi-omics data. We provide an overview of computational methods for modeling of gene regulatory networks, including some that have been applied towards the study of an interacting host and pathogen. In sum, comprehensive characterizations of host-fungal pathogen systems are now possible, and utilization of these cutting-edge multi-omics strategies may yield advances in better understanding of both host biology and fungal pathogens at a systems scale.
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Affiliation(s)
- Luka Culibrk
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carys A. Croft
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Scott J. Tebbutt
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Prevention of Organ Failure (PROOF) Centre of Excellence, Vancouver, British Columbia, Canada
- Department of Medicine, Division of Respiratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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20
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Li Z, Liang J, Shen J, Qiu G, Weng X. Thoracolumbar Scoliosis Due to Cryptococcal Osteomyelitis: A Case Report and Review of the Literature. Medicine (Baltimore) 2016; 95:e2613. [PMID: 26844472 PMCID: PMC4748889 DOI: 10.1097/md.0000000000002613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cryptococcus neoformans causes opportunistic infections in immunocompromised patients, with vertebral osteomyelitis being a very rare involvement.This study is to present a case of thoracolumbar scoliosis occurring in the setting of cryptococcal osteomyelitis.Pharmacological intervention with anticryptococcal medicine and medical management of immune hemolytic anemia were administered. After initial acute stabilization, she underwent spinal debridement and fusion on October 29, 2008. She eventually recovered fully from this episode with no subsequent mechanical instability or neurological deficits on subsequent clinic follow-ups.To the best of our knowledge, there have been no reports describing the onset of spinal cryptococcal osteomyelitis along with immune hemolytic anemia. We suggest a comprehensive algorithm for the diagnosis of vertebral cryptococcal osteomyelitis.
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Affiliation(s)
- Zheng Li
- From the Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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21
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Zhou Y, Yuikawa N, Nakatsuka H, Maekawa H, Harashima S, Nakanishi Y, Kaneko Y. Core regulatory components of the PHO pathway are conserved in the methylotrophic yeast Hansenula polymorpha. Curr Genet 2016; 62:595-605. [PMID: 26794724 PMCID: PMC4929164 DOI: 10.1007/s00294-016-0565-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 01/04/2016] [Accepted: 01/06/2016] [Indexed: 12/26/2022]
Abstract
To gain better understanding of the diversity and evolution of the gene regulation system in eukaryotes, the phosphate signal transduction (PHO) pathway in non-conventional yeasts has been studied in recent years. Here we characterized the PHO pathway of Hansenula polymorpha, which is genetically tractable and distantly related to Saccharomyces cerevisiae and Schizosaccharomyces pombe, in order to get more information for the diversity and evolution of the PHO pathway in yeasts. We generated several pho gene-deficient mutants based on the annotated draft genome of H. polymorpha BY4329. Except for the Hppho2-deficient mutant, these mutants exhibited the same phenotype of repressible acid phosphatase (APase) production as their S. cerevisiae counterparts. Subsequently, Hppho80 and Hppho85 mutants were isolated as suppressors of the Hppho81 mutation and Hppho4 was isolated from Hppho80 and Hppho85 mutants as the sole suppressor of the Hppho80 and Hppho85 mutations. To gain more complete delineation of the PHO pathway in H. polymorpha, we screened for UV-irradiated mutants that expressed APase constitutively. As a result, three classes of recessive constitutive mutations and one dominant constitutive mutation were isolated. Genetic analysis showed that one group of recessive constitutive mutations was allelic to HpPHO80 and that the dominant mutation occurred in the HpPHO81 gene. Epistasis analysis between Hppho81 and the other two classes of recessive constitutive mutations suggested that the corresponding new genes, named PHO51 and PHO53, function upstream of HpPHO81 in the PHO pathway. Taking these findings together, we conclude that the main components of the PHO pathway identified in S. cerevisiae are conserved in the methylotrophic yeast H. polymorpha, even though these organisms separated from each other before duplication of the whole genome. This finding is useful information for the study of evolution of the PHO regulatory system in yeasts.
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Affiliation(s)
- Ying Zhou
- Yeast Genetic Resources Laboratory, Graduate School of Engineering, Osaka University, Osaka, 565-0871, Japan
| | - Naoya Yuikawa
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, 565-0871, Japan
| | - Hiroki Nakatsuka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, 565-0871, Japan
| | - Hiromi Maekawa
- Yeast Genetic Resources Laboratory, Graduate School of Engineering, Osaka University, Osaka, 565-0871, Japan
| | - Satoshi Harashima
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, 565-0871, Japan.,Division of Applied Microbial Technology, Graduate School of Engineering, Sojo University, Kumamoto, 860-0082, Japan
| | - Yoichi Nakanishi
- Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601, Japan
| | - Yoshinobu Kaneko
- Yeast Genetic Resources Laboratory, Graduate School of Engineering, Osaka University, Osaka, 565-0871, Japan.
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